When I move the character's body, the movement is like an alien
this model is rigged. control by using pose mode and moving the bones, they control the limbs.
some bones may point the elbows, hopefully, IK is set up, where you move a bone and the limb bends instead of you having to rotate
just control with the little gray knobs for that foot
each one corresponds to a moveable limb and/or jointthank Aoradon for https://docs.blender.org/manual/ko/dev/rigging/index.html